Colloidal Aggregation in Mixtures of Partially Miscible Liquids by Shear-Induced Capillary Bridges
Colloidal Aggregation in Mixtures of Partially Miscible Liquids by Shear-Induced Capillary Bridges
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DOI：
10.1021/la501060w
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发表时间：
2014-05-27
期刊：
影响因子：
3.9
通讯作者：
Clegg, Paul S.
中科院分区：
文献类型：
--
作者：
Hijnen, Niek;Clegg, Paul S.
我们研究了胶体二氧化硅颗粒悬浮在各种部分互溶液体混合物中的剪切诱导聚集。所研究的系统的共同特征是，在二元液体混合物的液-液相分离之后，一相完全润湿颗粒。我们已经探索了其中颗粒润湿组分的量不足以引起相分离的组合物。随着润湿组分比例的增加，我们发现剪切诱导聚集发生的显著浓度范围。这一现象的宏观特征得到了证实，对于这一现象的观察，大多数情况下使用在室温下部分互溶的液体对是非常方便的。测量揭示的吸附的少数组分的胶体颗粒表明，颗粒之间的毛细凝聚导致所观察到的聚集。这种聚集行为的可能的微观特征进行了讨论。最后，这些系统的整体画面被勾勒为非平衡液-液相图，其中在双节点之外有一个区域的剪切诱导聚集。
We have studied shear-induced aggregation of colloidal silica particles suspended in a variety of partially miscible liquid mixtures. The shared characteristic of the investigated systems is that after liquid liquid phase separation of the binary liquid mixtures one phase completely wets the particles. We have explored compositions where there are insufficient quantities of the particle wetting component to induce phase separation. As the proportion of the wetting component is increased, we find a significant concentration range where shear-induced aggregation takes place. The macroscopic characteristics of this phenomenon are demonstrated, for which observations were greatly facilitated by mostly using liquid pairs partially miscible at room temperature. Measurements revealing the adsorption of the minority component to colloidal particles show that capillary condensation between particles causes the observed aggregation. The likely microscopic features underlying this aggregation behavior are then discussed. Finally, the overall picture of these systems is sketched as a nonequilibrium liquid liquid phase diagram, in which outside the binodal there is a region of shear-induced aggregation.